X0206 3 2018-02-08 0 0001130598 Onconova Therapeutics, Inc. ONTX 0001404574 683 Capital Management, LLC 3 COLUMBUS CIRCLE SUITE 2205 NEW YORK NY 10019 0 0 1 0 0001380126 683 Capital Partners, LP C/O 683 CAPITAL GP, LLC 3 COLUMBUS CIRCLE, SUITE 2205 NEW YORK NY 10019 0 0 1 0 Common Stock, par value $0.01 per share 2464934 I By 683 Capital Partners, LP Series A Convertible Preferred Stock Purchase Warrant 1.01 2018-02-12 2019-12-31 Series A Convertible Preferred Stock 200000 I By 683 Capital Partners, LP This Form 3 is filed jointly by 683 Capital Management, LLC ("683 Management"), 683 Capital Partners, LP ("683 Partners") and Ari Zweiman (collectively, the "Reporting Persons"). Each of the Reporting Persons may be deemed to be a member of a Section 13(d) group that collectively owns more than 10% of the Issuer's outstanding shares of Common Stock. Each of the Reporting Persons disclaims beneficial ownership of the securities reported herein except to the extent of his or its pecuniary interest therein. Represents securities held directly by 683 Partners. 683 Management is the investment manager of 683 Partners. Ari Zweiman is the Managing Member of 683 Management. As a result, each of 683 Management and Ari Zweiman may be deemed to beneficially own the securities held by 683 Partners. Each share of Series A Convertible Preferred Stock of the Issuer is convertible into 10 shares of Common Stock of the Issuer, subject to adjustment. /s/ Ari Zweiman, Managing Member of 683 Capital GP, LLC, in its capacity as general partner of 683 Capital Partners, LP 2018-02-12 /s/ Ari Zweiman, Managing Member of 683 Capital Management, LLC 2018-02-12 /s/ Ari Zweiman 2018-02-12